The regulation of phenolic acid synthesis in Bacillus subtilis

1971 ◽  
Vol 17 (1) ◽  
pp. 53-59 ◽  
Author(s):  
B. L. Walsh ◽  
W. J. Peters ◽  
R. A. J. Warren
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Phenolic Acid ◽  
Iron Uptake ◽  
Acid Synthesis ◽  
Benzoic Acids ◽  
Dihydroxybenzoic Acid ◽  
Uptake Capacity ◽  
Iron Deficient ◽  
Substituted Benzoic Acids

Formation of the enzymes synthesizing 2,3-dihydroxybenzoic acid (DHB) in Bacillus subtilis is repressed by iron. DHB does not appear to be involved in regulating its own biosynthesis. Hemin may be involved in regulating DHB synthesis. DHB synthetase is inhibited by several m-substituted benzoic acids. The inhibitors do not affect the growth rate of B. subtilis and DHB appears not to be necessary for growth under the conditions used. Inhibition of DHB synthesis during growth under iron-deficient conditions reduces the iron uptake capacity of B. subtilis.

The mechanism of iron uptake in Bacillus subtilis

1970 ◽  
Vol 16 (12) ◽  
pp. 1285-1291 ◽  
Author(s):  
W. J. Peters ◽  
R. A. J. Warren
Keyword(s):  
Bacillus Subtilis ◽  
Phenolic Compounds ◽  
Phenolic Acids ◽  
Phenolic Acid ◽  
Iron Uptake ◽  
Hydroxamic Acids ◽  
Acid Complex ◽  
Iron Deficient ◽  
Active Transport System ◽  
Energy Dependent

A variety of phenolic compounds and hydroxamic acids reduced or prevented phenolic acid and coproporphyrin accumulation by iron-deficient cultures of Bacillus subtilis, but only if they were added to cultures with levels of iron which alone did not prevent accumulation. The compounds also increased iron uptake by iron-deficient cultures and norma) cultures. When radioactive catechol or 2,3-dihydroxybenzoic acid was used to increase iron uptake by iron-deficient cells, only very low levels of radioactivity remained associated with the cells. It is suggested that B. subtilis produces phenolic acids to solubilize iron; that other phenolic compounds or hydroxamic acids may substitute for the phenolic acids produced by B. subtilis; that the iron: phenolic acid complex does not enter the cell; and that the iron is removed from the complex at the cell surface and taken into the cell by an energy-dependent active transport system.

The accumulation of phenolic acids and coproporphyrin by iron-deficient cultures of Bacillus subtilis

1970 ◽  
Vol 16 (12) ◽  
pp. 1179-1185 ◽  
Author(s):  
W. J. Peters ◽  
R. A. J. Warren
Keyword(s):  
Iron Deficiency ◽  
Phenolic Acids ◽  
Phenolic Acid ◽  
Biosynthetic Pathway ◽  
Culture Medium ◽  
Iron Complex ◽  
Dihydroxybenzoic Acid ◽  
Uptake Capacity ◽  
Iron Deficient ◽  
Acid Accumulation

Phenolic acids started to accumulate before coproporphyrin in cultures of B. subtilis grown under conditions of iron deficiency. If hemin synthesis was reduced or prevented, both phenolic acid accumulation and the iron-uptake capacity of the cells were decreased. A mutant strain unable to synthesize hemin accumulated phenolic acids only if the culture medium was extracted with hydroxyquinoline to remove residual iron. A mixture of iron and 2,3-dihydroxybenzoic acid was more effective than iron alone in reducing coproporphyrin accumulation by iron-deficient cultures. It is suggested that phenolic acids are produced by B. subtilis to solubilize the iron in the medium; under iron deficiency the biosynthetic pathway for phenolic acids is derepressed so that residual iron in the medium will be made available to the cell as the phenolic acid: iron complex.

Kinetics and Mechanism of Decomposition of 1,3-Bis(4-methylphenyl)triazene Catalyzed with Substituted Benzoic Acids in 25% Aqueous Methanol-General or Specific Catalysis?

1994 ◽  
Vol 59 (9) ◽  
pp. 2029-2041
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná
Keyword(s):  
Benzoic Acids ◽  
Hammett Equation ◽  
Aqueous Methanol ◽  
Mechanism Of Decomposition ◽  
Kinetics Of Decomposition ◽  
Independent Variable ◽  
Amino Derivatives ◽  
Substituted Benzoic Acids ◽  
The Individual ◽  
Kinetics Of

The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effect is described by the Hammett equation. The statistically best model in which the observed rate constant is a superposition of a term describing the dependence on proton concentration and a term describing the dependence on the product of concentrations of proton and conjugated base is valid with the presumption of complete proton transfer from the catalyst acid to substrate, which has been proved. The behaviour of 4-dimethylamino, 4-amino, and 3-amino derivatives is anomalous (lower catalytic activity as compared with benzoic acid). This supports the presumed participation of conjugated base in the title process.

Kinetic study of hydrolysis of benzoates. part xxvii. ortho substituent effect in alkaline hydrolysis of phenyl esters of substituted benzoic acids in aqueous Bu4NBr

2009 ◽  
Vol 74 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Signe Vahur ◽  
Oksana Travnikova ◽  
Ilmar A. Koppel
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Pure Water ◽  
Substituent Effects ◽  
Benzoic Acids ◽  
Resonance Effects ◽  
The Media ◽  
Substituted Benzoic Acids ◽  
Hydrolysis Of ◽  
Ortho Substituent

The second-order rate constants k (in dm3 mol–1 s–1) for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5, have been measured spectrophotometrically in aqueous 0.5 and 2.25 M Bu4NBr at 25 °C. The substituent effects for para and meta derivatives were described using the Hammett relationship. For the ortho derivatives the Charton equation was used. For ortho-substituted esters two steric scales were involved: the EsB and the Charton steric (υ) constants. When going from pure water to aqueous 0.5 and 2.25 M Bu4NBr, the meta and para polar effects, the ortho inductive and resonance effects in alkaline hydrolysis of phenyl esters of substituted benzoic acids, became stronger nearly to the same extent as found for alkaline hydrolysis of C6H5CO2C6H4-X. The steric term of ortho-substituted esters was almost independent of the media considered. The rate constants of alkaline hydrolysis of ortho-, meta- and para-substituted phenyl benzoates (X-C6H4CO2C6H5, C6H5CO2C6H4-X) and alkyl benzoates, C6H5CO2R, in water, 0.5 and 2.25 M Bu4NBr were correlated with the corresponding IR stretching frequencies of carbonyl group, (ΔνCO)X.

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